Diabetes drug Avandia enhances heart risks, finds study

14 September, 2007

The drug Avandia, used by millions of diabetics to control blood sugar, greatly increases their risk of heart attack and heart failure, say researchers.

However, Avandia, made by GlaxoSmithKline, does not increase a user’s overall risk of death, the new study has found.

Dr Sonal Singh, lead author of the study and assistant professor of internal medicine at Wake Forest University School of Medicine in Winston-Salem,
North Carolina, the United States, says “the balance of risks and benefits has shifted, and this needs to be factored into the equation.”

One in 30 patients taking rosiglitazone (Avandia) over a year will have heart failure, and that is very substantial, according to Dr Sonal Singh. And, one in 220 patients taking Avandia will have a heart attack, which is also very substantial.

Patients should talk to their doctors about the potential risks and benefits of the drug, Dr Singh suggests.

The study is published in the September 12, 2007, issue of the Journal of the American Medical Association. Another study in the same issue of the
journal has found that Actos (pioglitazone), a diabetes drug in the same class as Avandia, actually reduces the risk of heart attack, stroke and death, even while it increases the risk for serious heart failure.

According to Dr A Michael Lincoff, lead author of the study and vice-chairman for research in the department of cardiovascular medicine at the Cleveland Clinic, “this study shows that Actos, used for sugar control, provides an additional benefit of reducing cardiovascular complications, and this is very strong reassurance.”

It is yet unclear as to what the new conclusions mean for this class of drugs, called thiazolidinediones. Previous studies have indicated cardiovascular risks. In August 2007, the United States Food and Drug Administration (FDA) had mandated stricter labeling, including ‘black-box’ warnings, for the medications.

For the first study, Dr Sonal Singh and his colleagues conducted a meta-analysis of four randomised trials of Avandia involving over 14,000 patients.

In the analysis, Avandia increased the risk of heart attack by 42% and doubled the risk of heart failure, similar to findings of a previous study. In this analysis, however, Avandia did not increase the risk of death from cardiovascular causes.

With an estimated 3.5 million or more patients in the United States taking Avandia, the public health impact could be substantial, the authors point out. This could translate into more than 4,000 excess heart attacks and 9,000 excess heart failure events.

For the second study, also a meta-analysis, Dr Lincoff and his colleagues looked at data from 19 trials involving more than 16,000 participants that looked at Actos and cardiovascular complications. According to the authors of the study, Takeda Pharma, manufacturer of Actos, funded the analysis and provided the data from the trials, but was not involved in any of the analysis.

Like Avandia, Actos also raised users’ risk for heart failure, this time by about 40%.

However, unlike Avandia, patients receiving Actos had an 18% lower risk of heart attack, stroke or death than patients in the control group.